Mercurial > hg
view tests/test-push-r.t @ 26375:3686fa2b8eee
windows: insert file positioning call between reads and writes
fopen() and fdopen() have a unique-to-Windows requirement that
transitions between read and write operations in files opened
in modes r+, w+, and a+ perform a file positioning call
(fsetpos, fseek, or rewind) in between. While the MSDN docs don't
say what will happen if this is not done, observations reveal
that Python raises an IOError with errno 0. Furthermore, I
/think/ this behavior isn't deterministic. But I can reproduce
it reliably with subsequent patches applied that open revlogs
in a+ mode and perform both reads and writes.
This patch introduces a proxy class for file handles opened
in r+, w+, and a+ mode on Windows. The class intercepts calls
and audits whether a file positioning function has been called
between read and write operations. If not, a dummy, no-op seek
to the current file position is performed. This appears to be
sufficient to "trick" Windows into allowing transitions between
read and writes without raising errors.
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Sun, 27 Sep 2015 18:46:53 -0700 |
| parents | f2719b387380 |
| children | 24ea47037186 |
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$ hg init test $ cd test $ hg unbundle "$TESTDIR/bundles/remote.hg" adding changesets adding manifests adding file changes added 9 changesets with 7 changes to 4 files (+1 heads) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg up tip 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd .. $ for i in 0 1 2 3 4 5 6 7 8; do > echo > mkdir test-"$i" > hg --cwd test-"$i" init > hg -R test push -r "$i" test-"$i" > cd test-"$i" > hg verify > cd .. > done pushing to test-0 searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 1 changesets, 1 total revisions pushing to test-1 searching for changes adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 1 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 2 changesets, 2 total revisions pushing to test-2 searching for changes adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 1 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 3 changesets, 3 total revisions pushing to test-3 searching for changes adding changesets adding manifests adding file changes added 4 changesets with 4 changes to 1 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 4 changesets, 4 total revisions pushing to test-4 searching for changes adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 1 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 2 changesets, 2 total revisions pushing to test-5 searching for changes adding changesets adding manifests adding file changes added 3 changesets with 3 changes to 1 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 3 changesets, 3 total revisions pushing to test-6 searching for changes adding changesets adding manifests adding file changes added 4 changesets with 5 changes to 2 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 2 files, 4 changesets, 5 total revisions pushing to test-7 searching for changes adding changesets adding manifests adding file changes added 5 changesets with 6 changes to 3 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 3 files, 5 changesets, 6 total revisions pushing to test-8 searching for changes adding changesets adding manifests adding file changes added 5 changesets with 5 changes to 2 files checking changesets checking manifests crosschecking files in changesets and manifests checking files 2 files, 5 changesets, 5 total revisions $ cd test-8 $ hg pull ../test-7 pulling from ../test-7 searching for changes adding changesets adding manifests adding file changes added 4 changesets with 2 changes to 3 files (+1 heads) (run 'hg heads' to see heads, 'hg merge' to merge) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 4 files, 9 changesets, 7 total revisions $ cd ..